This applies to any browser. On occasion, and i don't know why, the auto proxy selection can cause browser connection issues. By setting it to none, which it should be using the majority of the time anyway, it remove the software's ability to question whether there are proxy settings. So switching it, though may not solve your issue, is not hurting anything either.
I actually had a problem similar to this and that was what caused 404 errors. It's worth a try and can be undone if it's not the issue. Restart your browser after you change it.